Multiple receiver line deployment and recovery

ABSTRACT

Embodiments described herein relate to an apparatus and method of transferring seismic equipment to and from a marine vessel and subsurface location. In one embodiment, a marine vessel is provided. The marine vessel includes a deck having a plurality of seismic sensor devices stored thereon, two remotely operated vehicles, each comprising a seismic sensor storage compartment, and a seismic sensor transfer device comprising a container for transfer of one or more of the seismic sensor devices from the vessel to the sensor storage compartment of at least one of the two remotely operated vehicles.

CROSS-REFERENCES TO RELATED APPLICATIONS

This application claims the benefit of priority under 35 U.S.C. §120 asa divisional of U.S. patent application Ser. No. 13/671,645 filed Nov.8, 2012, which claims the benefit of priority under 35 U.S.C. §120 as acontinuation of U.S. patent application Ser. No. 12/343,136 filed Dec.23, 2008, each of which are incorporated by reference herein in theirentirety.

FIELD OF THE INVENTION

Embodiments described herein relate to the field of seismic explorationin a marine environment. More particularly, to an apparatus and methodof transferring seismic equipment to and from an operations platform andan underwater location.

DESCRIPTION OF THE RELATED ART

Seismic exploration in deep water typically utilizes seismic sensordevices stored on a first marine vessel that are transferred from thefirst vessel and placed on or near the seafloor or seabed. These devicesare typically referred to as Ocean Bottom Cabling (OBC) or Ocean BottomSeismometer (OBS) systems, such as Seafloor Seismic Recorders (SSR's).These SSR devices contain seismic sensors and electronics in sealedpackages, and record seismic data on-board the devices while deployed onthe seabed as opposed to digitizing and transmitting the data to anexternal recorder while deployed. The recorded data is obtained byretrieving the devices from the seabed to a location on the first vesseland downloading the recorded data from the devices to a recorder whileonboard the first vessel.

In typical operation, hundreds or thousands of OBS units are deployedfrom the first vessel to the seabed from the first vessel. In oneconventional method, the OBS units are deployed using a remotelyoperated vehicle (ROV) tethered to the first vessel. The ROV is loweredbelow the surface of the water and positioned subsurface. One or moreOBS units are placed by the ROV on the seabed at predetermined locationsin a linear row, which may be known as a receiver line. When at leastone receiver line consisting of a suitable number of the OBS units isformed, a seismic survey may be performed by providing a source signal,such as an acoustic or vibrational signal. Reflected signals from theseabed and underlying structures are recorded on the one or more OBSunits. The source signal or “shot” is typically provided by a secondmarine vessel, which may be known as a gun boat.

In the deployment of the OBS units, the speed at which the OBS units canbe deployed is primarily limited to the speed at which the equipment canbe towed through the water. Specifically, support equipment for the ROV,such as an umbilical cable and a tether management system (TMS) havelarge drag coefficients. The drag of these components typically limitthe speed of the first vessel. Thus, the number of OBS units that can bedeployed or retrieved in a given time period is limited. The deploymenttime also affects the efficiency of the seismic survey as the secondvessel must wait until the at least one receiver line is laid prior toshooting. The first vessel continues laying other receiver lines whilethe second vessel is shooting, but as shooting is often completed priorto completion of the next receiver line, the second vessel must againwait until the second receiver line is formed.

Therefore, what is needed is a method and apparatus for transferringseismic sensor devices to and from the first vessel and/or the ROV in amanner that maximizes the number of seismic sensor devices deployed andretrieved, and provides a buffer for a second vessel.

SUMMARY OF THE INVENTION

Embodiments described herein relate to an apparatus and method oftransferring seismic sensor devices to and from a marine vessel andsubsurface location.

In one embodiment, a marine vessel is provided. The marine vesselincludes a deck having a plurality of seismic sensor devices storedthereon, two remotely operated vehicles, each comprising a seismicsensor storage compartment, and a seismic sensor transfer devicecomprising a container for transfer of one or more of the seismic sensordevices from the vessel to the sensor storage compartment of at leastone of the two remotely operated vehicles.

In another embodiment, a marine vessel is provided. The marine vesselincludes at least three cranes disposed thereon, a plurality of seismicsensor devices stored on the deck, a remotely operated vehicle coupledto the vessel, the remotely operated vehicle comprising a seismic sensorstorage compartment, and a seismic sensor transfer device comprising acontainer for transfer of one or more seismic sensor devices from thevessel to the remotely operated vehicle.

In another embodiment, a method for performing a seismic survey in amarine environment is provided. The method includes deploying a firstremotely operated vehicle from a first vessel moving in a direction,deploying a seismic sensor transfer device from the first vessel havinga plurality of sensor devices disposed therein, transferring theplurality of sensor devices from the seismic sensor transfer device to asensor storage compartment of the first remotely operated vehicle at asubsurface location, and placing each of the first plurality of sensordevices in selected locations in the marine environment using the firstremotely operated vehicle.

In another embodiment, a method for performing a seismic survey in amarine environment is provided. The method includes deploying a firstremotely operated vehicle from a first vessel, the first vessel poweredto operate in a direction at a speed greater than zero knots, placing afirst plurality of sensor devices in selected locations in the marineenvironment using the first remotely operated vehicle, deploying aseismic sensor storage container from the first vessel having a secondplurality of sensor devices disposed thereon, and transferring thesecond plurality of sensor devices to the first remotely operatedvehicle at a subsurface location.

In another embodiment, a method for deploying seismic sensor devices ina marine environment is provided. The method includes deploying aremotely operated vehicle from a vessel, powering the vessel to operateat a first speed in a first direction, the first speed being greaterthan zero knots, operating the remotely operated vehicle at a secondspeed to deploy a first plurality of sensor devices, the second speedbeing greater than the first speed at intermittent intervals, whereinthe remotely operated vehicle deploys the first plurality of sensordevices in a pattern relative to the first direction of the vessel,deploying a seismic sensor container from the vessel, the seismic sensorcontainer having a second plurality of sensor devices disposed thereon,and transferring the second plurality of sensor devices onto theremotely operated vehicle.

In another embodiment, a method for deploying a plurality of sensordevices in a marine environment is provided. The method includesdeploying at least a first remotely operated vehicle from a vessel, thefirst remotely operated vehicle comprising an onboard sensor storagecompartment, loading the onboard sensor storage compartment with aplurality of sensor devices, operating the vessel in a first direction,and placing the sensor devices in a pattern in the marine environment,wherein the pattern comprises at least three linear rows of sensordevices relative to the first direction.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the manner in which the above recited features of the presentinvention can be understood in detail, a more particular description ofthe invention, briefly summarized above, may be had by reference toembodiments, some of which are illustrated in the appended drawings. Itis to be noted, however, that the appended drawings illustrate onlytypical embodiments of this invention and are therefore not to beconsidered limiting of its scope, for the invention may admit to otherequally effective embodiments.

FIG. 1 is an isometric schematic view of one embodiment of a seismicoperation in deep water.

FIG. 2 is an isometric schematic view of another embodiment of a seismicoperation in deep water.

FIG. 3 is a schematic plan view of one embodiment of a seismic sensordevice layout.

FIG. 4 is a schematic plan view of another embodiment of a seismicsensor device layout.

FIG. 5 is a schematic plan view of another embodiment of a seismicsensor device layout.

FIG. 6 is a schematic plan view showing a continuation of the seismicsensor device layout of FIG. 5.

FIG. 7 is a schematic plan view showing a continuation of the seismicsensor device layout of FIG. 6.

FIG. 8 is a flow chart showing one embodiment of a deployment method.

FIG. 9 is a flow chart showing another embodiment of a deploymentmethod.

To facilitate understanding, identical reference numerals have beenused, where possible, to designate identical elements that are common tothe figures. It is also contemplated that elements disclosed in oneembodiment may be beneficially utilized on other embodiments withoutspecific recitation.

DETAILED DESCRIPTION

Embodiments described herein relate to an apparatus and method fortransferring one or more seismic sensor devices to or from a marinevessel on a surface of a body of water and a subsurface marine locationusing a remotely operated vehicle (ROV). The ROV may be an autonomousunderwater vehicle (AUV) or any apparatus capable of operatingautonomously or semi-autonomously in a marine environment. The marinevessel may be a boat, a ship, a barge or a floating platform adapted tostore and transfer a plurality of seismic sensor devices. Each of theseismic sensor devices as described herein may be a discrete subsurfacesensor, for example, sensors and/or recorders, such as ocean bottomseismometers (OBS), seafloor seismic recorders (SSR), and similardevices. SSR's are typically re-usable and may be recharged and servicedbefore re-deployment. The seismic sensor devices may be configured tocommunicate by wireless connections or configured to communicate throughcables. The seismic sensor devices contain seismic sensors andelectronics in sealed packages, and record seismic data within anon-board recorder while deployed on the seabed as opposed to digitizingand transmitting the data to an external recorder. The recorded data isobtained by retrieving the seismic sensor devices from the seabed usingthe ROV or AUV.

FIG. 1 is an isometric schematic view of one embodiment of a seismicoperation in deep water facilitated by a first marine vessel 5. Thefirst vessel 5 is positioned on a surface 10 of a water column 15 andincludes a deck 20 which supports operational equipment. At least aportion of the deck 20 includes space for a plurality of sensor deviceracks 90 where seismic sensor devices are stored. The sensor deviceracks 90 may also include data retrieval devices and/or sensorrecharging devices.

The deck 20 also includes one or more cranes 25A, 25B attached theretoto facilitate transfer of at least a portion of the operationalequipment, such as an ROV and/or seismic sensor devices, from the deck20 to the water column 15. For example, a crane 25A coupled to the deck20 is configured to lower and raise an ROV 35A, which transfers andpositions one or more sensor devices 30 on a seabed 55. The ROV 35A iscoupled to the first vessel 5 by a tether 46A and an umbilical cable 44Athat provides power, communications, and control to the ROV 35A. Atether management system (TMS) 50A is also coupled between the umbilicalcable 44A and the tether 46A. Generally, the TMS 50A may be utilized asan intermediary, subsurface platform from which to operate the ROV 35A.For most ROV 35A operations at or near the seabed 55, the TMS 50A can bepositioned approximately 50 feet above seabed 55 and can pay out tether46A as needed for ROV 35A to move freely above seabed 55 in order toposition and transfer seismic sensor devices 30 thereon.

A crane 25B is coupled to a stern of the first vessel 5, or otherlocations on the first vessel 5. Each of the cranes 25A, 25B may be anylifting device and/or launch and recovery system (LARS) adapted tooperate in a marine environment. In this embodiment, the crane 25B iscoupled to a seismic sensor transfer device 100 by a cable 70. Thetransfer device 100 may be a drone, a skid structure, a basket, or anydevice capable of housing one or more sensor devices 30 therein. Thetransfer device 100 may be a structure configured as a magazine adaptedto house and transport one or more sensor devices 30. In one embodiment,the transfer device 100 is configured as a sensor device storage rackfor transfer of sensor devices 30 from the first vessel 5 to the ROV35A, and from the ROV 35A to the first vessel 5. The transfer device 100may include an on-board power supply, a motor or gearbox, and/or apropulsion system (all not shown). Alternatively, the transfer device100 may not include any integral power devices and/or not require anyexternal or internal power source. If needed, the cable 70 may providepower and/or control to the transfer device 100. Alternatively, thecable 70 may be an umbilical, a tether, a cord, a wire, a rope, and thelike, that is configured solely for support of the transfer device 100.

The ROV 35A includes a seismic sensor device storage compartment 40 thatis configured to store one or more seismic sensor devices 30 therein fora deployment and/or retrieval operation. The storage compartment 40 maybe a magazine, a rack, or a container configured to store the seismicsensor devices. The storage compartment 40 may also include a movableplatform having the seismic sensor devices thereon, such as a carouselor linear platform configured to support and move the seismic sensordevices 30 therein. In one embodiment, the seismic sensor devices 30 maybe deployed on the seabed 55 and retrieved therefrom by operation of themovable platform. In this embodiment, the ROV 35A may be positioned at apredetermined location above or on the seabed 55 and seismic sensordevices 30 are rolled, conveyed, or otherwise moved out of the storagecompartment 40 at the predetermined location. In another embodiment, theseismic sensor devices 30 may be deployed and retrieved from the storagecompartment 40 by a robotic device 60, such as a robotic arm, an endeffector or a manipulator, disposed on the ROV 35A.

For example, in a deployment operation, a first plurality of seismicsensor devices, comprising one or more sensor devices 30, may be loadedinto the storage compartment 40 while on the first vessel 5 in apre-loading operation. The ROV 35A, having the storage compartmentcoupled thereto, is then lowered to a subsurface position in the watercolumn 15. The ROV 35A utilizes commands from personnel on the firstvessel 5 to operate along a course to transfer the first plurality ofseismic sensor devices 30 from the storage compartment 40 and deploy theindividual sensor devices 30 at selected locations on the seabed 55.Once the storage compartment 40 is depleted of the first plurality ofseismic sensor devices 30, the transfer device 100 is used to ferry asecond plurality of seismic sensor devices 30 as a payload from firstvessel 5 to the ROV 35A.

The transfer device 100 is preloaded with a second plurality of seismicsensor devices 30 while on or adjacent the first vessel 5. When asuitable number of seismic sensor devices 30 are loaded onto thetransfer device 100, the transfer device 100 may be lowered by crane 25Bto a selected depth in the water column 15. The ROV 35A and transferdevice 100 are mated at a subsurface location to allow transfer of thesecond plurality of seismic sensor devices 30 from the transfer device100 to the storage compartment 40. When the transfer device 100 and ROV35A are mated, the second plurality of seismic sensor devices 30contained in the transfer device 100 are transferred to the storagecompartment 40 of the ROV 35A. Once the storage compartment 40 isreloaded, the ROV 35A and transfer device 100 are detached or unmatedand seismic sensor device placement by ROV 35A may resume. In oneembodiment, reloading of the storage compartment 40 is provided whilethe first vessel 5 is in motion. If the transfer device 100 is emptyafter transfer of the second plurality of seismic sensor devices 30, thetransfer device 100 may be raised by the crane 25B to the vessel 5 wherea reloading operation replenishes the transfer device 100 with a thirdplurality of seismic sensor devices 30. The transfer device 100 may thenbe lowered to a selected depth when the storage compartment 40 needs tobe reloaded. This process may repeat as needed until a desired number ofseismic sensor devices 30 have been deployed.

Using the transfer device 100 to reload the ROV 35A at a subsurfacelocation reduces the time required to place the seismic sensor devices30 on the seabed 55, or “planting” time, as the ROV 35A is not raisedand lowered to the surface 10 for seismic sensor device reloading.Further, mechanical stresses placed on equipment utilized to lift andlower the ROV 35A are minimized as the ROV 35A may be operated below thesurface 10 for longer periods. The reduced lifting and lowering of theROV 35A may be particularly advantageous in foul weather and/or roughsea conditions. Thus, safety of personnel and lifetime of equipment maybe enhanced as the ROV 35A and related equipment are not raised abovesurface 10, which may cause the ROV 35A and related equipment to bedamaged, or pose a risk of injury to the vessel personnel.

Likewise, in a retrieval operation, the ROV 35A utilizes commands frompersonnel on the first vessel 5 to retrieve each seismic sensor device30 that was previously placed on seabed 55. The retrieved seismic sensordevices 30 are placed into the storage compartment 40 of the ROV 35A. Inone embodiment, the ROV 35A may be sequentially positioned adjacent eachseismic sensor device 30 on the seabed 55 and the seismic sensor devices30 are rolled, conveyed, or otherwise moved from the seabed 55 to thestorage compartment 40. In another embodiment, the seismic sensordevices 30 may be retrieved from the seabed 55 by a robotic device 60disposed on the ROV 35A.

Once the storage compartment 40 is full or contains a pre-determinednumber of seismic sensor devices 30, the transfer device 100 is loweredto a position below the surface 10 and mated with the ROV 35A. Thetransfer device 100 may be lowered by crane 25B to a selected depth inthe water column 15, and the ROV 35A and transfer device 100 are matedat a subsurface location. Once mated, the retrieved seismic sensordevices 30 contained in the storage compartment 40 are transferred tothe transfer device 100. Once the storage compartment 40 is depleted ofretrieved sensor devices, the ROV 35A and transfer device 100 aredetached and sensor device retrieval by ROV 35A may resume. Thus, thetransfer device 100 is used to ferry the retrieved seismic sensordevices 30 as a payload to the first vessel 5, allowing the ROV 35A tocontinue collection of the seismic sensor devices 30 from the seabed 55.In this manner, sensor device retrieval time is significantly reduced asthe ROV 35A is not raised and lowered for sensor device unloading.Further, safety issues and mechanical stresses placed on equipmentrelated to the ROV 35A are minimized as the ROV 35A may be subsurfacefor longer periods.

In this embodiment, the first vessel 5 may travel in a first direction75, such as in the +X direction, which may be a compass heading or otherlinear or predetermined direction. The first direction 75 may alsoaccount for and/or include drift caused by wave action, current(s)and/or wind speed and direction. In one embodiment, the plurality ofseismic sensor devices 30 are placed on the seabed 55 in selectedlocations, such as a plurality of rows R_(n) in the X direction (R₁ andR₂ are shown) and/or columns C_(n) in the Y direction (C₁-C₃ are shown),wherein n equals an integer. In one embodiment, the rows R_(n) andcolumns C_(n) define a grid or array, wherein each row R_(n) comprises areceiver line in the width of a sensor array (X direction) and/or eachcolumn C_(n) comprises a receiver line in a length of the sensor array(Y direction). The distance between adjacent sensor devices 30 in therows is shown as distance L_(R) and the distance between adjacent sensordevices 30 in the columns is shown as distance L_(C). While asubstantially square pattern is shown, other patterns may be formed onthe seabed 55. Other patterns include non-linear receiver lines and/ornon-square patterns. The pattern(s) may be pre-determined or result fromother factors, such as topography of the seabed 55. In one embodiment,the distances L_(R) and L_(C) may be substantially equal and may includedimensions between about 60 meters to about 400 meters, or greater. Thedistance between adjacent seismic sensor devices 30 may be predeterminedand/or result from topography of the seabed 55 as described above.

The first vessel 5 is operated at a speed, such as an allowable or safespeed for operation of the first vessel 5 and any equipment being towedby the first vessel 5. The speed may take into account any weatherconditions, such as wind speed and wave action, as well as currents inthe water column 15. The speed of the vessel may also be determined byany operations equipment that is suspended by, attached to, or otherwisebeing towed by the first vessel 5. For example, the speed is typicallylimited by the drag coefficients of components of the ROV 35A, such asthe TMS 50A and umbilical cable 44A, as well as any weather conditionsand/or currents in the water column 15. As the components of the ROV 35Aare subject to drag that is dependent on the depth of the components inthe water column 15, the first vessel speed may operate in a range ofless than about 1 knot. In this embodiment, wherein two receiver lines(rows R₁ and R₂) are being laid, the first vessel includes a first speedof between about 0.2 knots and about 0.6 knots. In other embodiments,the first speed includes an average speed of between about 0.25 knots,which includes intermittent speeds of less than 0.25 knots and speedsgreater than about 1 knot, depending on weather conditions, such as waveaction, wind speeds, and/or currents in the water column 15.

During a seismic survey, one receiver line, such as row R₁ may bedeployed. When the single receiver line is completed a second vessel 80is used to provide a source signal. The second vessel 80 is providedwith a source device 85, which may be a device capable of producingacoustical signals or vibrational signals suitable for obtaining thesurvey data. The source signal propagates to the seabed 55 and a portionof the signal is reflected back to the seismic sensor devices 30. Thesecond vessel 80 may be required to make multiple passes, for example atleast four passes, per a single receiver line (row R₁ in this example).During the time the second vessel 80 is making the passes, the firstvessel 5 continues deployment of a second receiver line. However, thetime involved in making the passes by the second vessel 80 is muchshorter than the deployment time of the second receiver line. Thiscauses a lag time in the seismic survey as the second vessel 80 sitsidle while the first vessel 5 is completing the second receiver line.

In this embodiment, the first vessel 5 utilizes one ROV 35A to laysensor devices to form a first set of two receiver lines (rows R₁ andR₂) in any number of columns, which may produce a length of eachreceiver line of up to and including several miles. In one embodiment,the two receiver lines (rows R₁ and R₂) are substantially parallel. Whena single directional pass of the first vessel 5 is completed and thefirst set (rows R₁, R₂) of seismic sensor devices 30 are laid to apredetermined length, the second vessel 80, provided with the sourcedevice 85, is utilized to provide the source signal. The second vessel80 is typically required to make eight or more passes along the tworeceiver lines to complete the seismic survey of the two rows R₁ and R₂.

While the second vessel 80 is shooting along the two rows R₁ and R₂, thefirst vessel 5 may turn 180 degrees and travel in the −X direction inorder to lay seismic sensor devices 30 in another two rows adjacent therows R₁ and R₂, thereby forming a second set of two receiver lines. Thesecond vessel 80 may then make another series of passes along the secondset of receiver lines while the first vessel 5 turns 180 degrees totravel in the +X direction to lay another set of receiver lines. Theprocess may repeat until a specified area of the seabed 55 has beensurveyed. Thus, the idle time of the second vessel 80 is minimized asthe deployment time for laying receiver lines is cut approximately inhalf by deploying two rows in one pass of the vessel 5.

Although only two rows R₁ and R₂ are shown, the sensor device 30 layoutis not limited to this configuration as the ROV 35A may be adapted tolayout more than two rows of sensor devices in a single directional tow.For example, the ROV 35A may be controlled to lay out between three andsix rows of sensor devices 30, or an even greater number of rows in asingle directional tow. The width of a “one pass” run of the firstvessel 5 to layout the width of the sensor array is typically limited bythe length of the tether 46A and/or the spacing (distance L_(R)) betweensensor devices 30.

FIG. 2 is an isometric schematic view of another embodiment of a seismicoperation in deep water facilitated by the first vessel 5. In thisembodiment, the first vessel 5 has multiple ROV's operating therefrom.In FIG. 2, by way of example and not limitation, two ROV 35A and ROV 35Bare shown. Each of the ROV's 35A, 35B include a respective TMS 50A, 50B,tether 46A, 46B, and umbilical cable 44A, 44B. The first ROV 35A iscoupled to the first crane 25A on the port side 6A of the first vessel 5and the second ROV 35B is coupled to a third crane 25C on the starboardside 6B of the first vessel 5.

The first ROV 35A and the second ROV 35B are configured to provide alayout pattern for the plurality of sensor devices 30 on the seabed 55on both sides of the first vessel 5. Each of the ROV's 35A and 35B maybe controlled independently or synchronously to travel in a direction orcourse relative to the vessel 5 to deploy the sensor devices 30 on theseabed in a pre-determined pattern. In one aspect, each of the ROV's 35Aand 35B deploy a plurality of rows and columns as described above. Inthe embodiment depicted in FIG. 2, rows R₁-R₄ and columns C₁-C₄ define,respectively, the width and the length of a seismic array.

In this embodiment, ROV 35A moves in a first pattern relative to thevessel direction 75 to deploy a plurality of rows of sensor devices 30(rows R₁ and R₂ are shown) while ROV 35B moves in a second patternrelative to the vessel direction 75 to deploy a plurality of rows ofsensor devices 30 (rows R₃ and R₄ are shown). The pattern of the firstROV 35A may be the same or different than the pattern of the second ROV35B. The distance between adjacent sensor devices 30 in the rows R₁-R₄is shown as distance L_(R) and the distance between adjacent sensordevices 30 in the columns C₁-C₄ is shown as distance L_(C). While asubstantially square pattern is shown, other patterns may be formed onthe seabed 55. Other patterns include non-linear receiver lines and/ornon-square patterns. The pattern(s) may be pre-determined or result fromother factors, such as topography of the seabed 55. In one embodiment,the distances L_(R) and L_(C) may be substantially equal and may includedimensions between about 60 meters to about 400 meters, or greater. Thedistance between adjacent seismic sensor devices 30 may be predeterminedand/or result from topography of the seabed 55 as described above.

In the embodiment shown, the rows R₁-R₄ form a first set of fourreceiver lines and the rows are complete when a sufficient number ofcolumns are provided. Once the first set is completed, the second vesselmay provide the source signal. In this embodiment, the second vesselmust make at least 16 passes to shoot the four rows R₁-R₄. During thistime, the first vessel 5 is laying a second set of receiver lines, whichmay include four rows. Thus, the deployment time of the four receiverlines (rows R₁-R₄) by the vessel 5 is effectively reduced by about 25percent as compared to deployment of a single receiver line. Theminimized deployment time results in less idle time of the secondvessel, which results in greater efficiency and reduced costs of theseismic survey.

As in the embodiment shown in FIG. 1, the rows R₁, R₂ formed by ROV 35Aand rows R₃, R₄ formed by the ROV 35B are not limited as described andmay consist of three, four, five, six, or greater number of rows. In oneexample, each of the ROV's 35A, 35B may lay four sensor devices 30 toform four rows such that eight sensor devices 30 comprise each column.In this example, when a sufficient number of columns are provided toform the rows, eight receiver lines define the present width of thearray. The lateral pattern (Y direction) used to deploy each row istypically chosen to maintain forward motion of the vessel 5 and minimizestopping forward motion of the vessel 5. Thus the lateral pattern todeploy additional rows may be limited by the speed of the ROV's 35A,35B, specifically the speed of the ROV's 35A, 35B in the Y direction.The lateral (Y direction) distance from the first vessel 5 is limited bya length of the tethers 46A, 46B. Thus, in one embodiment, the maximaldistance for placement of seismic sensor devices 30 in rows R₁ and R₄from the first vessel 5 is substantially equal to the length of thetethers 46A, 46B. In this embodiment, the maximal distance from thefirst vessel 5 where the seismic sensor devices 30 in rows R₁ and R₄ arepositioned are between about 600 meters to about 1200 meters, or greaterfrom the first vessel 5. In other embodiments, the maximal distance isbetween about 1000 meters to about 1600 meters from the first vessel 5.

FIG. 3 is a schematic plan view of one embodiment of a seismic sensordevice layout 300 which, in one embodiment, comprises a plurality ofreceiver lines (rows R₁-R₆). Points 301A-309A represent locations forplacement of seismic sensor devices on a seabed along the port side 6Aof the first vessel 5 and points 301B-309B represent locations forplacement of seismic sensor devices on the seabed along the starboardside 6B of the first vessel 5. While not shown, an ROV operating on theport side 6A and an ROV operating on the starboard side 6B facilitateplacement of the seismic sensor devices at the points 301A-309A and301B-309B.

In this embodiment, seismic sensor device placement by the ROV 35Astarts at point 301A on the port side 6A and placement of the seismicsensor devices by the ROV 35B on the starboard side 6B starts at point301 B. The port side 6A and starboard side 6B placement then proceeds inthe +Y direction to points 302A and 302B, respectively. The port side 6Apattern (and starboard side pattern) then proceeds in a +Y direction topoint 303A (and point 303B), then in the X direction to point 304A (andpoint 304B), then in the −Y direction to point 305A and point 306A(points 305B and 306B). In this embodiment, identical X-Y patterns P_(A)and P_(B) are defined by points 301A-307A on the port side 6A and points301B-307B on the starboard side 6B. A repeating X-Y pattern is thenexecuted at 307A and 307B until a sufficient number of columns C_(n) areformed.

FIG. 4 is a schematic plan view of another embodiment of a seismicsensor device layout 400 which, in one embodiment, comprises a pluralityof receiver lines (rows R₁-R₆). Points 401A-409A represent locations forplacement of seismic sensor devices on a seabed along the port side 6Aof the first vessel 5 and points 401B-409B represent locations forplacement of seismic sensor devices on the seabed along the starboardside 6B of the first vessel 5. While not shown, an ROV operating on theport side 6A and an ROV operating on the starboard side 6B facilitateplacement of the seismic sensor devices at the points 401A-409A and401B-409B.

In this embodiment, the port side 6A placement by the ROV 35A starts atpoint 401A and the starboard side 6B placement by the ROV 35B starts atpoint 401B. The port side placement then proceeds in the +Y direction topoint 402A and 403A, then in the X direction to point 404A, then in the-Y direction to point 405A and point 406A. The starboard side 6Bplacement proceeds in the −Y direction to point 402B and 403B, then inthe X direction to point 404B, then in the +Y direction to 405B and406B. In this embodiment, a mirror-image of X-Y patterns P_(A) and P_(B)are defined by points 401A-407A on the port side 6A and points 401B-407Bon the starboard side 6B. A repeating mirrored X-Y pattern is thenexecuted at 407A and 407B until a sufficient number of columns C_(n) areformed.

FIG. 5 is a schematic plan view of another embodiment of a seismicsensor device layout 500. The array layout is similar to the arraylayout 300 and pattern of FIG. 3 with the exception of sensor devicesbeing laid over a portion of the points 301A-312A on the port side 6A ofthe first vessel 5 and a portion of the points 301B-312B on thestarboard side 6B of the first vessel 5. The sensor devices that havebeen positioned on the respective points 301A-306A and 301B-306B arereferenced as sensor devices 501A-506A on the port side 6A of the firstvessel 5 and sensor devices 501B-506B on the starboard side 6B of thefirst vessel 5. Additionally, the port side 6A ROV 35A is shown as wellas the starboard side 6B ROV 35B.

As described in FIGS. 1 and 2, each of the ROV's 35A, 35B include anintegral storage compartment 40 which are not shown in the plan view ofFIG. 5. In one embodiment, each of the storage compartments 40 containsa first plurality of seismic sensor devices 30. For example, the storagecompartment 40 may have a capacity of about 14 seismic sensor devices.The sensor devices may be pre-loaded into each storage compartment 40 onthe first vessel 5 for subsequent transfer to each point. Once thesensor devices have been laid on the points in the array layout 500, thestorage compartments 40 are replenished without surfacing the ROV's 35A,35B. In this embodiment, a transfer device 100 is towed behind the firstvessel 5 to facilitate reloading of sensor devices in the storagecompartment of ROV 35A. In one embodiment, the pre-loading and reloadingof the storage compartments 40 of each ROV 35A, 35B with seismic sensordevices 30 are unequal to facilitate a staggered or alternatingreloading operation between each ROV 35A, 35B.

In this embodiment, after sensor device 506A is deployed at point 306A,the ROV 35A is reloaded. The transfer device 100 is towed behind thefirst vessel 5 below the vessel 5. The ROV 35A may travel to the towedtransfer device 100 in a course 550 to a position adjacent the transferdevice 100. The ROV 35A and transfer device 100 are mated in a manner totransfer the seismic sensor devices to the storage compartment 40. Whilethe ROV 35A is reloaded, the storage compartment 40 of the ROV 35B maynot be depleted and continues deployment on the starboard side 6B. Inthis embodiment, the ROV 35A is reloaded with additional sensor devicesby the transfer device 100 while the ROV 35B continues deployment ofsensor devices. After the storage compartment of ROV 35A is reloaded,the ROV 35A and transfer device 100 are detached and the ROV 35A travelsin a course 555 toward the next deployment point 307A. Each of thecourses 550, 555 may be a lateral direction, a diagonal direction, or alinear or serpentine path. The reloading operation is staggered betweenthe ROV's 35A and 35B to enhance efficiency of the deployment of thearray. During reloading, the first vessel 5 may be stopped, slowed ormaintained at a speed that was used during deployment of seismic sensordevices along the array.

FIG. 6 is a schematic plan view showing a continuation of the seismicsensor device layout 500 of FIG. 5. In this embodiment, after sensordevice 509B is deployed at point 309B, the ROV 35B is reloaded. ROV 35A,which has been reloaded with a second plurality of sensor devices asshown in FIG. 5, continues deployment on the port side 6A (shown assensor devices 601A-603A). In this embodiment, the ROV 35B is reloadedwith a second plurality of sensor devices by the transfer device 100while the ROV 35A continues deployment of sensor devices.

FIG. 7 is a schematic plan view showing a continuation of the seismicsensor device layout 500 of FIG. 6. In this embodiment, after sensordevice 612A is deployed at point 318A, the ROV 35A is reloaded. ROV 35B,which has been reloaded with a second plurality of sensor devices,continues deployment on the starboard side 6B (shown as sensor devices701B-709B). In this embodiment, the ROV 35A is reloaded with a thirdplurality of sensor devices by the transfer device 100 while the ROV 35Bcontinues deployment of sensor devices.

As shown in the embodiments of FIGS. 5-7, eighteen sensor devices havebeen deployed at points 301A-318A by ROV 35A and eighteen sensor deviceshave been deployed at points 301B-318B by ROV 35B for a total of thirtysix sensor devices in one-pass of the vessel. The reloading operation toreplenish the ROV storage compartment is alternated between the ROV's35A, 35B to enhance efficiency of the layout of the array. During thedeployment of the rows, the speed of the first vessel 5 may bemaintained at a substantially constant speed.

In one operational embodiment, an example of deploying sensor devicesusing the embodiments described in FIGS. 5-7 will be described. Thefirst vessel 5 speed may be maintained or averaged at about 0.25 knotsalong direction 75 while a port side 6A ROV 35A and a starboard side ROV35B may be operated at speeds of less than about 10 knots. The distancesL_(R) and L_(C) between points may be about 400 meters. A firstplurality of sensor devices 30, consisting of six sensor devices, may bepreloaded into ROV 35A and a first plurality of sensor devices 30,consisting of nine sensor devices, may be preloaded into ROV 35B.Seismic sensor devices 501A-506A may be deployed and ROV 35A should bereloaded with a second plurality of seismic sensor devices as shown inFIG. 5. The second plurality of seismic sensor devices may comprisetwelve sensor devices. In this embodiment, the first vessel 5 may bemaintained at about 0.25 knots during the reloading operation.

The first vessel 5 proceeds in the direction 75 and ROV 35A continuesdeployment of seismic sensor devices beginning at point 307A while ROV35B places a seismic sensor device 507B at point 307B as shown in FIG.6. Both ROV's 35A and 35B may continue deployment along the patternsuntil deployment of seismic sensor device 509B by ROV 35B.

After deployment of seismic sensor device 509B by ROV 35B, ROV 35B maybe reloaded with a second plurality of seismic sensor devices, as shownin FIG. 6. The second plurality of sensor devices may comprise anothertwelve seismic sensor devices. The first vessel 5 may be maintained atabout 0.25 knots during the reloading operation. The first vessel 5proceeds in the direction 75 and ROV 35B may continue deployment ofseismic sensor devices beginning at point 310B while ROV 35A places aseismic sensor device 604A at point 310A as shown in FIG. 7. Both ROV's35A, 35B may continue deployment along the pattern as shown. After ROV35A deploys a sensor device 612A at point 318A, the ROV 35A may bereloaded with a third plurality of seismic sensor devices, for example,another twelve seismic sensor devices. The pattern may continue until asufficient number of columns are completed. After completion, the secondvessel (not shown) may begin shooting, which may involve at least 24passes of the second vessel. During the shooting, the first vessel maybegin another one pass lay of another six receiver lines.

FIG. 8 is a flow chart showing one embodiment of a deployment method800. The method 800 may be used to deploy a plurality of seismic sensorreceiver lines in one pass of a first vessel as described in the aboveembodiments. At 810, at least one ROV is deployed from a vessel. At 815,the vessel is operated in a first direction relative to a seabed. Thefirst direction may be a compass heading or other linear orsubstantially linear direction. At 820, a plurality of seismic sensordevices are deployed from the at least one ROV to form at least tworeceiver lines on the seabed along the first direction. In oneembodiment, the at least two receiver lines are substantially parallelto the first direction. In another embodiment, the at least two receiverlines are substantially parallel to each other.

FIG. 9 is a flow chart showing another embodiment of a deployment method900. The method 900 may be used to deploy a plurality of seismic sensorreceiver lines in one pass of a first vessel as described in the aboveembodiments. The method begins at 910 using at least two ROV's coupledto the first vessel in a body of water. At 915, the vessel operates in afirst direction in the body of water. The first direction may be acompass heading or other linear and/or directional path. At 920, aplurality of sensor devices are deployed from the at least two ROV'swhile the vessel travels in the first direction. The plurality of sensordevices may be deployed in a plurality of receiver lines comprising apattern. The pattern may be an X/Y pattern in a mirror-image, anidentical X/Y pattern, or other pattern using the at least two ROV's. Inone embodiment, the plurality of receiver lines are substantiallyparallel to the first direction. In another embodiment, the plurality ofreceiver lines are substantially parallel to each other.

The deployment of multiple receiver lines has been determinedempirically as described in FIG. 1. While setting the vessel speed tosafe operating speed, the number of seismic sensor devices deployed in aspecific time period was greater than the conventional deployment methodin the same time period. In one example according to the embodimentdescribed in FIG. 1, two receiver lines were deployed at a rate of aboutten seismic sensor units per hour, while the conventional one passmethod of deploying ten seismic sensor units in a single receiver linetook approximately five hours. In one specific example using theembodiment described in FIG. 1, two receiver lines were deployed having5 seismic sensor devices each (ten seismic sensor units total) at 400meter spacings (distances L_(R) and L_(C)). The vessel 5 was slowed toabout one-half of the conventional speed. In this example, the one passdeployment of the two receiver lines resulted in a time savings of aboutthirty minutes as compared to conventional deployment of a singlereceiver line (ten seismic sensor units) in one pass at twice the travelspeed. This time saving may be extrapolated to multiple columns up toand including several miles and when the receiver lines are completed,the second vessel will be utilized for many hours or days, dependentupon the number of columns or length of the receiver lines. While thesecond vessel is shooting, the first vessel continues to deploy otherreceiver lines in one pass. Thus, a buffer time for the first vessel maybe created using the one pass multiple receiver line deployment method.

Using the embodiments described herein, the deployment time of seismicsensor devices is significantly minimized, which allows the secondvessel to operate with minimal or no idle time waiting for receiver lineplacement. The decreased deployment time also minimizes the time thefirst vessel is operating on the water. The decreased time on the wateralso minimizes labor costs and fuel usage. The decreased time on thewater also allows seismic array layouts to be completed in a time framethat coincides with fair weather windows. Thus, deployment (and/orretrieval) of the sensor devices is less likely to be suspended due toperiods of foul weather. As the seismic sensor devices include batterieswith a limited operational time, the shortened deployment time alsoincreases the probability that the survey can be complete beforeexhaustion of the batteries of the seismic sensor devices. For example,a seismic survey utilizing one thousand sensor devices may be completedin one week, including deployment and shooting, as opposed toconventional deployment methods which may take many weeks to cover thesame area. Retrieval of the sensor devices may be completed in anotherweek using the methods described herein.

While the foregoing is directed to embodiments of the present invention,other and further embodiments of the invention may be devised withoutdeparting from the basic scope thereof, and the scope thereof isdetermined by the claims that follow.

1. A marine vessel, comprising: a deck configured to store a pluralityof seismic sensor devices; two remotely operated vehicles, eachcomprising a seismic sensor storage compartment; and a seismic sensortransfer device comprising a container for transfer of one or more ofthe seismic sensor devices from the vessel to the sensor storagecompartment of at least one of the two remotely operated vehicles. 2.The marine vessel of claim 1, further comprising: a first crane and asecond crane coupled to the vessel.
 3. The marine vessel of claim 2,wherein one of the remotely operated vehicles is coupled to the firstcrane and the seismic sensor transfer device is coupled to the secondcrane.
 4. The marine vessel of claim 3, wherein the seismic sensortransfer device is configured to be positioned at a subsurface location.5. The marine vessel of claim 4, wherein the remotely operated vehicleand the seismic sensor transfer device are configured to mate at thesubsurface location to transfer seismic sensor devices therebetween. 6.The marine vessel of claim 1, wherein the seismic sensor transfer deviceis configured to be towed behind the vessel.
 7. A marine vessel,comprising: at least two cranes disposed on the vessel; a deckconfigured to store a plurality of seismic sensor devices; a remotelyoperated vehicle coupled to the vessel, the remotely operated vehiclecomprising a seismic sensor storage compartment; and a seismic sensortransfer device configured to transfer one or more seismic sensordevices from the vessel to the remotely operated vehicle.
 8. The marinevessel of claim 7, wherein the remotely operated vehicle is coupled to afirst crane of the at least two cranes and the seismic sensor transferdevice is coupled to a second crane of the at least two cranes.
 9. Themarine vessel of claim 8, wherein the seismic sensor transfer device ispositioned at a subsurface location.
 10. The marine vessel of claim 9,wherein the remotely operated vehicle and the seismic sensor transferdevice are configured to mate at the subsurface location to transferseismic sensor devices therebetween.
 11. The marine vessel of claim 10,wherein the seismic sensor transfer device comprises a conveyorconfigured to facilitate transfer of the seismic sensor devices.
 12. Themarine vessel of claim 10, wherein the seismic sensor transfer devicecomprises a rack configured to facilitate transfer of the seismic sensordevices.
 13. The marine vessel of claim 10, wherein the seismic sensortransfer device comprises a movable platform configured to facilitatetransfer of the seismic sensor devices.
 14. The marine vessel of claim10, wherein the seismic sensor transfer device comprises a trayconfigured to facilitate transfer of the seismic sensor devices.
 15. Themarine vessel of claim 7, wherein the seismic sensor transfer device isconfigured to be towed behind the vessel. 16-57. (canceled)
 58. Themarine vessel of claim 1, wherein the seismic sensor transfer device andthe remotely operated vehicle are configured to transfer a seismicsensor device therebetween at a subsurface location above a seabed. 59.The marine vessel of claim 1, wherein the seismic sensor transfer deviceand the remotely operated vehicle are configured to transfer a seismicsensor device therebetween at a subsurface location at a seabed.
 60. Themarine vessel of claim 3, wherein the seismic sensor transfer device isconfigured to be positioned at a subsurface location based on anintermittent time interval.
 61. The marine vessel of claim 7, whereinthe seismic sensor transfer device is positioned at a subsurfacelocation above a seabed.
 62. The marine vessel of claim 7, wherein atleast one of the seismic sensor transfer device and the seismic sensorstorage compartment comprises at least one of a container, a drone, askid structure, a transfer skid, a basket, a rack, and a magazine.